I moved from Pool to Twenty ten the appearance of my blog and I lost everything, side bar with widgets, archive, tag clouds blog roll and buttons. I can easily replace the blog roll and the buttons, but what about the archive and tags??? lost forever???
The widgets should be in an “inactive widgets” box on your widgets page, with all their settings maintained. If you drag them back into your sidebar, they should appear just like they were before. If you’re looking for the widgets page, check out these docs: